The first example of tautomerism in 2-aminopyrroles: effect of structure and solvent

Rosa, Michael De; Arnold, David; O’Hare, Bernie

doi:10.1016/j.tetlet.2008.10.100

Cited by 6 publications

(11 citation statements)

References 14 publications

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“…Melting points are uncorrected. 1 H and 13 C NMR spectra were obtained in CDCl 3 , acetone-d 6 or DMSO-d 6 . Chemical shifts were reported in parts per million with the residual solvent peak or TMS used as an internal standard.…”

Section: Methodsmentioning

confidence: 99%

“…1 H NMR spectra were recorded at 400 MHz and are tabulated as follows: chemical shift, multiplicity (s singlet, d doublet, t triplet, q quartet, m multiplet, br broad), number of protons, and coupling constants. 13 C NMR were recorded at 100 MHz using a proton-decoupled pulse sequence with a d 1 of 5 sec, and are tabulated by observed peak. All of the chloro-pyrimidines (3-9) used in this study were commercially available.…”

Section: Methodsmentioning

confidence: 99%

“…No evidence for tautomerism of pyrroloaminopyrimidines 10-17 was detected. 13,14 Reaction was observed with all of the chloropyrimidines, although the results with 2-chloropyrimidine were problematic and not reported in Table 1 and Scheme 2. Previous work indicated that 2-chloropyrimidine was not very reactive.…”

Section: Introductionmentioning

confidence: 99%

“…Stability of the pyrroloaminopyrimidines 10-17 appeared to depend on how electron-withdrawing the pyrimidines attached to amino group were. 12 Structures were supported by H 1 and C 13 NMR and HRMS. No evidence for tautomerism of pyrroloaminopyrimidines 10-17 was detected.…”

Section: Introductionmentioning

confidence: 99%

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Reaction of 3-aminopyrrole with chloropyrimidines to give pyrroloaminopyrimidines

Rosa¹,

Arnold²,

Wright³

et al. 2015

Arkivoc

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Reaction of 3-aminopyrrole with chloropyrimidines occured only at the 3-amino group. The activating group(s) (Cl, NO 2 or CF 3 ), their relative positions (C4/C6, C2, or C5), and the effect of added base (DIPEA) or acetic acid on the course of the reaction, was studied. When chloro groups were present on both C4/C6 and C2, the only or major product was from the displacement of the C4/C6 chloro group. Only in the reaction of 2,4,6-trichloropyrimidine was substitution at C2 competitive with reaction at C6. Both chloro groups of 2,4-dichloro-3-nitropyrimidine were displaced to give a novel compound with three-linked heterocyclic rings. Reactions of less reactive chloropyrimidines appeared to be favored by acid catalysis.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Reaction of 3-aminopyrrole with chloropyrimidines to give pyrroloaminopyrimidines

Rosa¹,

Arnold²,

Wright³

et al. 2015

Arkivoc

Self Cite

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“…The same was reported for secondary amino substituents only in the case of 23 (R = trichloropyrimidyl). Obviously, the conjugation imino nitrogen/substituent is strong enough to observe the imine tautomer 23b (Scheme 5.17) [55]. The proton transfer between the imine and enamine tautomers of 2-phenacylquinolines 24 (Scheme 5.18) in solution is slow on the NMR timescale [56].…”

Section: Imine-amine Tautomerismmentioning

confidence: 99%

NMR Spectroscopic Study of Tautomerism in Solution and in the Solid State

Kleinpeter

2013

Tautomerism

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Effect of Solvent Polarizability on the Keto/Enol Equilibrium of Selected Bioactive Molecules from the 1,3,4-Thiadiazole Group with a 2,4-Hydroxyphenyl Function

et al. 2017

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Three novel 1,3,4-tiadiazole-derived compounds with biological-activity, i.e., 4-(5-(methylamino)-1,3,4-thiadiazol-2-yl)benzene-1,3-diol (MDFT), 4-(5-(phenylamino)-1,3,4-thiadiazol-2-yl)benzene-1,3-diol (PhATB), and 4-(5-(4-chlorophenylamino)-1,3,4-thiadiazol-2-yl)benzene-1,3-diol (4-CIPhATB) were characterized with the use of several spectroscopic methods. Detailed UV-vis studies revealed keto/enol tautomerism of the examined compounds. The absorption spectra recorded in nonpolar solvents exhibited bands that were characteristic of keto tautomers, while in polar solvents the enol form is predominant. A number of spectra revealed the presence of both tautomeric forms in the solution. The keto/enol equilibria observed were both solvent- and temperature-dependent. The keto/enol equilibrium was also observed using FTIR spectroscopy. A detailed analysis of the spectroscopic data leads to a conclusion that the solvent-induced tautomerism of the selected compounds from the 1,3,4-thiadiazole group does not depend on the electric dipole moment of the solvent but more likely on its average electric polarizability. Additionally, a clear effect of the substituent present in the molecule on the tautomeric equilibrium in the selected 1,3,4-thiadiazole analogues was noted.

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The first example of tautomerism in 2-aminopyrroles: effect of structure and solvent

Cited by 6 publications

References 14 publications

Reaction of 3-aminopyrrole with chloropyrimidines to give pyrroloaminopyrimidines

Reaction of 3-aminopyrrole with chloropyrimidines to give pyrroloaminopyrimidines

NMR Spectroscopic Study of Tautomerism in Solution and in the Solid State

Effect of Solvent Polarizability on the Keto/Enol Equilibrium of Selected Bioactive Molecules from the 1,3,4-Thiadiazole Group with a 2,4-Hydroxyphenyl Function

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